Chemistry Reference
In-Depth Information
FIGURE 88
Dating methods.
Shortly after the discovery of radioactivity, at the begin-
ning of the twentieth century, it was found that the decay of radioactive elements could
be used to keep track of time. Many of the dating techniques developed since then
are, therefore, based on radioactive decay phenomena, but others, such as the hydra-
tion of obsidian, amino acid racemization, and dendrochronology, are based on other
physical, chemical, or biological phenomena.
